FIG 4.

Binding comparison of the antibody 53C10 to CA/04 HA and escape mutant HA in IFA. The chamber slide-cultured MDCK cells were infected by the CA/04 WT and escape mutant. At 24 h postinfection, the cells were fixed with 80% acetone, followed by staining with the primary antibody 53C10 (upper images) and the antibody targeting NP protein (FR-667; lower images). Virus-infected cells were detected by staining with NP-specific monoclonal antibody. DAPI was used to stain the nucleus blue. Scale bar: 20 μm.